Method and apparatus for manufacture of cold setting foundry moulds and cores

ABSTRACT

A method and means for making foundry moulds or cores from a cold setting sand/resin/catalyst mixture in which separate metered charges of sand and resin and sand and catalyst are supplied to a mixing chamber in which operates a rotary mixing element and when sufficient quantities of each charge have been supplied to the chamber for the core or mould being produced the resultant mixture is expelled from the chamber into a core or mould box by applying a blast of compressed air to the chamber.

United States Patent Edwards 1451 Dec. 5, 1972 [54] METHOD ANDAPPARATUSFOR 2,847,196 8/1958 Franklin et al. ..259/8 MANUFACTURE OF COLD SETTING3,439,733 4/1969 Miller et al ...164/2l x FOUNDRY MOULDS AND CORES3,472,307 10/1969 Godding ...l64/43 x 3,590, 7 1971 l ..l 4 [72]Inventor: Albert Edwards, Peterborough, En- 906 Bayhss eta 6 H00 glandOTHER PUBLICATIONS [73] Assignee: Baker Perkins Limited, Peter- ModemCasting; July, 1968; page 124' borough, England [22] Filed: July 13,1970 Primary Examiner-Robert D. Baldwin [21] AppL NOS 54,227Attorney-Larson, Taylor & Hinds 57 ABSTRACT [30] Foreign ApplicationPriority Data 1 A method and means for making foundry moulds or July 21,1969 Great Br1ta1n ..36,548/69 cores from a cold Settingsand/resin/catalyst mixture in which separatemetered charges of sand andresin and [52] U.S. Cl. ..164/21, 164/157, 164/200, sand and catalystare Supplied to a mixing chamber in 259/8 which operates a rotary mixingelement and when suf- [5 Cl. ..B22c ficient quantities of each chargehave been supplied to Field of Search 1 64/21, 3, 37, the chamber forthe core or mould being produced the 259/ 107 resultant mixture isexpelled from the chamber into a core or mould box by applying a blastof compressed [56] References Cited air to the chamber.

UNITED STATES PATENTS 12 Claims, 2 Drawing Figures 1,345,542 7/1920Hartshorn ..259/107 PATENTED B 5 m2 7 3.704.743

SHEET 1 OF 2 INVENTOR ALBERT EMRDS PA'TENTEDDEI: 5 m2 SHEET 2 [IF 2FIG.2.

INVENTOR ALBERT EDWARDS METHOD AND APPARATUS FOR MANUFACTURE OF COLDSETTING FOUNDRY MOULDS AND CORES It has been proposed for the productionof foundry moulds and cores to utilize a cold quick-settingsand/resin/catalyst mixture. Due to the nature of the mixtureconstituents, rapid chemical reactions take place when they are broughttogether and a problem has accordingly arisen in preparing moulds andcores therefrom.

According to the present invention, a sand/resin mixture and asand/catalyst mixture are supplied to a mixing chamber in which they areintermixed by a rotating mechanical mixing element, and when sufficientquantities of each mixture have been supplied to the chamber for a mouldor core being prepared, the resultant admixture is shot from the chamberinto a mould or core box by applying a blast of compressed gas(conveniently compressed air) to the chamber.

Further, according to the present invention, a sand/resin mixture and asand/catalyst mixture are supplied to a mixing chamber in which they areintermixed by a continuously rotating mechanical mixing element, andwhen sufficient quantities of each mixture have been supplied to thechamber for a mould or core being prepared, the resultant admixture isshot from the chamber directly into a mould or core box through anoutlet at the base of the chamber by applying a blast of compressed gas(conveniently compressed air) to the chamber.

The invention further provides apparatus for preparing foundry moulds orcores comprising a mixing chamber, a rotatable mixing element in thechamber, supply means for delivering a sand/resin mixture and asand/catalyst mixture to the chamber, drive means for rotating themixing element to intermix the mixtures as and when these are suppliedto the chamber, and mixture expelling means for supplying a blast ofcompressed gas to the chamber when metered quantities of the mixtureshave been supplied thereto to shoot the resultant admixture into a coreor mould box through an outlet of the chamber.

The invention also provides apparatus for preparing foundry moulds orcores comprising a mixing chamber having an outlet at its base, arotatable mixing element in the chamber, supply means for delivering asand/resin mixture and a sand/catalyst mixture to the chamber, drivemeans for continuously rotating the mixing element to intermix themixtures asand when these are supplied to the chamber, and mixtureexpelling means for supplying a blast of compressed gas to the chamberwhen metered quantities of the mixtures have been supplied thereto toshoot the resultant admixture into a core or mould box through saidoutlet.

In one form of the invention, the mixing element has a vertical shaftwith scimitar shaped mixer blades having vertical scraper members attheir outer extremities which extend the full depth of the chamber andwe have found that with this type of element a rotational speed of about60 100 R.P.M. is suitable.

The supply means may conveniently comprise a pair of combinedmixer-conveyor units each having a sand inlet, a resin or catalystinlet, and an internal mixer conveyor element in the form of a screw ora bladed shaft of the type described in British Pat. No. 1,051,651

which mixes the constituents as they are conveyed to an outletdischarging into the mixing chamber.

The invention will now be described by way of an example with referenceto the accompanying drawings in which FIG. 1 is a semi-diagrammatic sideview of one form of apparatus for making foundry moulds and cores, andFIG. 2 is a semi-diagrammatic'side view of another form of apparatus forthe same purpose.

Referring to FIG. 1, a pair of elevated combined mixer conveyor units 1and 2 having internal mixer conveyor elements (not shown) gate valvecontrolled sand feeds 3, and resin or catalyst inlets 4, dischargethrough gate valve controlled outlets 5 into a mixing chamber 6, havingan outlet 7 in its base, and a vertical shaft mixing element 8 withinclined radial mixing rods 9 and scraper blades 10 and 11, a motor 12being provided for rotating the mixing element 8 at about 200 250 R.P.M.Below the outlet 7 is vertically adjustable mounting arrangement 13 fora mould or core box, including vertically operable diaphragm clamps 27and horizontally operable diaphragm clamps 28 and outlet 7 is surroundedby a plate 14 with vent holes formed therein which plate, in use, coversa mould or core box which is lifted into contact with the plate by thevertically operable diaphragm clamps 27 and an adjusting cylinder 15 isprovided to set the mounting arrangement 13 in position for a particularbatch of core or mould boxes.

A compressed air reservoir 16 is connected with the mixing chamber 6 bya duct 17 including a control valve 18 and an exhaust branch 20 with avalve 19 leading from duct 17.

Drive means for the mixer conveyor units including a motor 21, clutch22, brake 23, gearbox 24 and chain drivers 25, is mounted on a rotarybase 26 so that the entire mixer conveyor and drive structure can beswivelled. A control circuit and timer means are provided so that theapparatus functions as follows:

Initially the gate valve controller mixer conveyor unit outlets 5 areopened and sand and catalyst and sand and resin are supplied to therespective units at controlled rates of flow with the conveyordrivesoperating. The mixtures are thus supplied to the chamber 6 where theyare intermixed by element 8 and during this phase of operation only aninsignificant quantity of mixture escapes through the outlet 7 due to abridging effect of the admixturev When a required amount of both thesand/resin and sand/catalyst mixtures have been supplied to the mixingchamber for a mould or core being formed, a timer terminates the supplyof sand, resin, and catalyst to the mixer-conveyor units and stops theirconveyor-mixer elements which causes the gate valves controlling theflow of mixtures into the mixing chamber to close.

Then while the mixing element 8 continues to rotate, a further timercloses valve 19 and opens the valve 18, thus subjecting the mouldingmixture charge in chamber 6 to a blast of compressed air which shootsthe mixture into the core or mould box which is vented through the holesin plate 14. Valve 18 remains open for a period sufficient to dischargethe reservoir 16 and is then closed and valve 19 is simultaneouslyopened to vent the core or mould box and chamber 6 to the atmosphere.

The diaphragm clamps are opened, the box removed and replaced by a freshone and the cycle repeated.

The, arrangement shown in FIG. 2 is similar to'that shown in FIG. 1, andlike references have been used to refer to like parts. ln this case,however, the mixing chamber 30 is'relatively shallow and incorporates arotatable mixing element having scimitar shaped mixer blades 31, theextremities of which extend vertically the height of the chamber. Thechamber outlet is controlled by a gate valve 32 and below the chamber isa frusto-conical chute 33 terminating in an outlet 7 and plate 14 likethose in the first embodiment.

Operation is similar to the FIG. 1 arrangement except that the gatevalve 32 is closed while the separate mixtures are supplied to chamber31 through outlet and then when sufficient mixture quantities have beensupplied, outlets 5 are closed, gate valve 31 is opened and thepneumatic system is operated in like manner to the FIG. 1 system so thatthe admixture from chamber 1 is shot into the mould or core box throughchute 33. In this arrangement the mixer element is rotated, duringmixing, at a speed of about 60 lOO R.P.M.

What I claim is:

1. Apparatus for preparing foundry moulds and cores from a cold quicksetting sand, resin and catalyst mixture comprising a stationary mixingchamber having a pair of inlets for the delivery thereto of two separatecharges, one charge being sand and resin and the other charge being sandand catalyst, said chamber further having an outlet and means forconnecting said outlet directly to a moulding box for delivery of themixture from the chamber to the mould box without additional operationson the mixture between said outlet and the mould box, supply means fordelivering said separate charges of said sand and resin and said sandand catalyst to said chamber, controlled valve means between the supplymeans and the chamber for sealing the supply of said charges to thechamber from said supply means when metered quantities of said chargeshave been delivered, a rotatable mixing element in the chamber, drivemeans for continuously rotating the mixing element while the two chargesare being introduced and while the mixture is being removed to form asubstantially complete mixture from said charges as said charges aresupplied to the chamber, a source of compressed gas, duct meansconnecting said source to the chamber and a controlled valve means insaid duct means for admitting a blast of compressed gas from said sourceto said chamber when said metered quantities of said charges have beensupplied to the chamber to shoot the mixture directly into a mouldingbox through said outlet without additional operations on the mixturebetween the said outlet and the moulded box.

2. Apparatus as claimed in claim 1, wherein said mixing element has avertical shaft with scimitar shaped mixer blades having vertical scrapermembers at their outer extremities extending substantially the fulldepth of the chamber.

3. Apparatus as claimed in claim 1, wherein said outlet is permanentlyopen.

4. Apparatus as claimed in claim 1, wherein said outlet is controlled bya sliding gate valve.

5. Apparatus as claimed in claim 1, wherein said supply means comprisesa pair of combined mixer conveyor-units each having a sand inlet, afurther inlet for binder and catalyst respectively and an internal mixerconveyor element for mixing the onstituents asthey are conveyed to anoutlet for disc argmg the mlxture into the mixing chamber.

6. Apparatus as claimed in claim 5, wherein each mixer conveyor unitoutlet has a sliding gate valve for sealing the chamber therefrom.

7. Apparatus as claimed in claim 1, wherein the mixing chamber isadapted to shoot the resultant mixture into a moulding box via a hollowmember.

8. Apparatus as claimed in claim 1, wherein a valve controlled exhaustbranch leads from said duct means.

9. Apparatus as claimed in claim 1, including a timer to control openingand closing of said valve means.

10. A method of preparing foundry moulds and cores by a substantiallycold curing process comprising the steps of: metering separately a firstcharge of sand and resin and a second charge of sand and catalyst,delivering the separate charges separately into a stationary mixingchamber, substantially completely mixing the two charges in the mixingchamber with a continuously operating rotating mixing element, and whensaid metered charges have been supplied to the mixing chamber removingthe mixture from the mixing chamber directly into a mould or core boxwithout the interposition of additional operating steps on the mixturebetween the chamber and the mould box, by directing a blast ofcompressed gas, introduced through a passage separate from the chargeinlet into the mixture in the chamber such that its energy is utilizedprimarily to move the mixture out of an outlet from the mixing chamberand directly into the mould or core box, the step of mixing the twocharges with the mixing element continuing as the charges are introducedinto and as the mixture is removed from the mixing chamber to effectsaid substantially complete mixing of the charges in the chamber.

11. A method according to claim 10, wherein valves control the openingsof charge inlets into the mixing chamber and of the compressed gas intothe mixing chamber, and including the step of coordinating the timing ofoperation of these valves.

12. A method according to claim 10, wherein the first and second chargesenter the mixing chamber at one end, the mixture is discharged at theother end, and wherein the blast of compressed gas is directed in adirection from the said one end towards the other end.

1. Apparatus for preparing foundry moulds and cores from a cold quicksetting sand, resin and catalyst mixture comprising a stationary mixingchamber having a pair of inlets for the delivery thereto of two separatecharges, one charge being sand and resin and the other charge being sandand catalyst, said chamber further having an outlet and means forconnecting said outlet directly to a moulding box for delivery of themixture from the chamber to the mould box without additional operationson the mixture between said outlet and the mould box, supply means fordelivering said separate charges of said sand and resin and said sandand catalyst to said chamber, controlled valve means between the supplymeans and the chamber for sealing the supply of said charges to thechamber from said supply means when metered quantities of said chargeshave been delivered, a rotatable mixing element in the chamber, drivemeans for continuously rotating the mixing element while the two chargesare being introduced and while the mixture is being removed to form asubstantially complete mixture from said charges as said charges aresupplied to the chamber, a source of compressed gas, duct meansconnecting said source to the chamber and a controlled valve means insaid duct means for admitting a blast of compressed gas from said sourceto said chamber when said metered quantities of said charges have beensupplied to the chamber to shoot the mixture directly into a mouldingbox through said outlet without additional operations on the mixturebetween the said outlet and the moulded box.
 2. Apparatus as claimed inclaim 1, wherein said mixing element has a vertical shaft with scimitarshaped mixer blades having vertical scraper members at their outerextremities extending substantially the full depth of the chamber. 3.Apparatus as claimed in claim 1, wherein said outlet is permanentlyopen.
 4. Apparatus as claimed in claim 1, wherein said outlet iscontrolled by a sliding gate valve.
 5. Apparatus as claimed in claim 1,wherein said supply means comprises a pair of combined mixer conveyorunits each having a sand inlet, a further inlet for binder and catalystrespectively and an internal mixer conveyor element for mixing theconstituents as they are conveyed to an outlet for discharging themixture into the mixing chamber.
 6. Apparatus as claimed in claim 5,wherein each mixer conveyor unit outlet has a sliding gate valve forsealing the chamber therefrom.
 7. Apparatus as claimed in claim 1,wherein the mixing chamber is adapted to shoot the resultant mixtureinto a moulding box via a hollow member.
 8. Apparatus as claimed inclaim 1, wherein a valve controlled exhaust branch leads from said ductmeans.
 9. Apparatus as claimed in claim 1, including a timer to controlopening and closing of said valve means.
 10. A method of preparingfoundry moulds and cores by a substantially cold curing processcomprising the steps of: metering separately a first charge of sand andresin and a second charge of sand and catalyst, delivering the separatecharges separately into a stationary mixing chamber, substantiallycompletely mixing the two charges iN the mixing chamber with acontinuously operating rotating mixing element, and when said meteredcharges have been supplied to the mixing chamber removing the mixturefrom the mixing chamber directly into a mould or core box without theinterposition of additional operating steps on the mixture between thechamber and the mould box, by directing a blast of compressed gas,introduced through a passage separate from the charge inlet into themixture in the chamber such that its energy is utilized primarily tomove the mixture out of an outlet from the mixing chamber and directlyinto the mould or core box, the step of mixing the two charges with themixing element continuing as the charges are introduced into and as themixture is removed from the mixing chamber to effect said substantiallycomplete mixing of the charges in the chamber.
 11. A method according toclaim 10, wherein valves control the openings of charge inlets into themixing chamber and of the compressed gas into the mixing chamber, andincluding the step of coordinating the timing of operation of thesevalves.
 12. A method according to claim 10, wherein the first and secondcharges enter the mixing chamber at one end, the mixture is dischargedat the other end, and wherein the blast of compressed gas is directed ina direction from the said one end towards the other end.